Fire alarm device

ABSTRACT

A self-contained independently operable audible-sound fire-alarm device sensitive to dangerously high ambient temperature comprising a spring motor geared to a driven oscillating escapement mechanism pivotally connected to a hammer arm to oscillate the hammer arm against a bell flange to sound the alarm. The hammer arm is normally held silent by a stop leg and an axially movable stop abutting the stop leg. The stop is moved axially out engagement with the stop leg by the angular movement of a wing cam lying in a cam groove of the stop. A temperature sensitive bimetal coil angularly moves the wing cam under increased temperature calculated to b3 dangerous to move the stop clear of the stop leg to allow oscillation of the hammer arm against the bell flange. The wing-cam and cam groove on the stop have a low-angle high-mechanical advantage inclined-plane relationship easily operated by and highly sensitive to movement of the bimetal coil when reacting to increased temperature.

United States Patent Joseph A. Bilotta 20500 Goddard Ave., Apt. 217, Detroit, Mich. 48234 211 Appl. No. 96,699

[22] Filed Dec. 10, 1970 [45] Patented Dec. 21, 1971 [72] Inventor [54] FIRE ALARM DEVICE 2 Claims, 7 Drawing Figs.

2,609,785 9/1952 Fink 3,292,570 12/1966 Hoffman Primary Examiner- Louis J. Capozi A!t0rneyWilliam T. Sevald bient temperature comprising a spring motor geared to a driven oscillating escapement mechanism pivotally connected to a hammer arm to oscillate the hammer arm against a bell flange to sound the alarm. The hammer arm is normally held silent by a stop leg and an axially movable stop abutting the stop leg. The stop is moved axially out engagement with the stop leg by the angular movement ofa wing cam lying in a cam groove of the stop. A temperature sensitive bimetal coil angularly moves the wing cam under increased temperature calculated to b3 dangerous to move the stop clear of the stop leg to allow oscillation of the hammer arm against the bell flange. The wing-cam and cam groove on the stop have a low-angle high-mechanical advantage inclined-plane relationship easily operated by and highly sensitive to movement of the bimetal coil when reacting to increased temperature.

PATENTED met an 3328;494

sum 1 [IF 2 //v VEN TOR 4 Jam/ ,4 A. 5/107:

By JAMM ATTORNEY PATENTED BEBE! ml 3; 6283194 SHEET 2 OF 2 INVEN TOR JOSE/9V ,4. B/ZOTTA A T TORNEV FIRE ALARM DEVICE This invention relates to fire alarms of the audible-sound type which are self contained and powered and in particular to novel easily operated and highly sensitive control means.

Alarms have been employed heretofore to provide a warning of fire, however the several devices of the prior art have not proven entirely satisfactory inasmuch as they are complicated in design and construction, expensive to manufacture, and do not have the necessary ease of operation in their sensing and control elements to insure that the device will work in case of fire.

With the foregoing in view, it is a primary object of the invention to provide an alarm device for warning of fire which is simple in design and construction, inexpensive to manufacture, easy to mount, use, and operate, and which has the necessary ease and positive action of the temperature-sensing elements and control actuation elements to give definite assurance that the device will work to give the alarm in case of fire.

An object of the invention is to provide a self-contained and independently operable alarm device so that it is not dependent on other elements for either power or actuation.

An object of the invention is to provide an alarm device which has a stop arm on the bell hammer leg normally abutting an axially moveable stop so that little force is needed to move the stop relative to the leg to the released position.

An object of the invention is to provide a circumferential or tangential cam groove in the stop for actuation by a cam to move the stop to the released position.

An object of the invention is to provide a winged cam having a low-angle inclined-plane cam surface engaging the cam groove of the stop to move the stop to the released position with angular movement of the cam.

An object of the invention is to provide a low-angle inclined-plane low-friction cam surface engaging the cam groove of the stop so that maximum mechanical advantage is available so that only minimal force is required to swing the cam to operate the stop.

An object of the invention is to swing the cam with a temperature-sensitive bimetal coil which swings the cam in the stop-releasing direction when the coil reacts to increased temperature.

These and other objects of the invention will become apparent by reference to the following description of an audiblesound fire-alarm device embodying the invention taken in connection with the accompanying drawings, in which:

FIG. 1 is a face elevation view of the device showing the bell housing and an auxiliary thermometer hand and dial with the housing cut away in the location of the alarm bimetal heatsensitive coil.

FIG. 2 is a rear elevational view of the device seen in FIG. 1 with the back plate removed showing the internal parts including the stop, cam, and the stop leg in the normal nonalarm position.

FIG. 3 is a partial view similar to FIG. 2 showing the parts in the released alarm position.

FIG. 4 is a side elevation view of the device seen in FIGS. 1 and 2 with bell housing cut away, and shown in cross section to reveal the interior parts taken in the direction of the arrow 4 of FIG. 2 and showing the control cam, stop and stop leg in detail.

FIG. 5 is a side elevational view of the device with the bell housing removed similar to FIG. 4 showing the spring motor drive train.

FIG. 6 is a detail view of the stop, wing cam, and stop leg as seen in FIG. 4, showing the normal position of the parts; and

FIG. 7 is a view similar to FIG. 6 showing the alarm position of the parts.

Referring now to the drawings wherein like numerals refer to like and corresponding parts throughout the several views, the alarm device disclosed thereon to illustrate the invention comprises an alarm device 10 having a frame including paired spaced frame plates 11 and 12. Studs 13 and spacers 14 secure the plates 10 and 11 together. A spring-powered motor 15 is positioned between the plates 11 and 112 and has a winding shaft 16, a coil spring 17 having opposited ends with one end anchored to the shaft 16, and drive gear 13 free on the shaft 16. The other end of the spring 17 is connected to the drive gear 18. A ratchet 19 on the winding shaft prevents rotation of the winding shaft 16 in the unwinding direction.

A second shaft 20 lies between the plates 11 and 12. A reduction gear set 21 on the second shaft 20 engages with the drive gear 18. A third shaft 22 lies between the plates 11 and 12. A pinion gear 23 on the third shaft 22 engages with the reduction gear set 21. An escapement star wheel 24 on the third shaft 22 is connected to the pinion gear 23. A fourth shaft 25 lies between the plates 11 and 12. An escapement lever 26 is pivoted on the shaft 25. The escapement lever 26 has a clevis end 27 in driven engagement with the star wheel 24 and an opposite end. A fifth shaft 28 lies between the plates 11 and 12. A hammer arm 29 has opposite ends with one end pivoted on the fifth shaft 28 and said other impact end 33 swingable outwardly of the plates 11 and 12. The escapement lever 26 is pivotally connected at 50 to the hammer arm 29 to oscillate the hammer arm 29.

A bell housing 30 has a central portion 31 secured to one plate 11 and 12 and a flange portion 32 surrounding the edges of the plates 11 and 12. The flange 32 is adapted to be hit by the hammer arm 29, impact end 33. The star wheel 24 upon rotation alternately cams the clevis end 27 of the escapement lever 26 to oscillate the escapement lever 26 to in turn oscillate the hammer arm 29 to move the hammer arm impact end 33 against the flange 32 of the bell housing 30 to create a loud ringing sound of alarm.

A stop leg 34 is connected to the hammer am 29 as by mutual connection to the shaft 23. A sixth shaft 35 lies between the plates 11 and 12. A stop 36 is axially slidably disposed on the sixth shaft 35 and has a normal axial position engaging the stop leg 34 to prevent oscillation of the hammer arm 29 and an alarm axial position out of engagement with the stop leg 34 to permit oscillation of the hammer arm 29. The stop 36 has a cam groove 37, a ridge or other means to engage a cam. A seventh shaft 51 lies between the plates 11 and 12. A low-friction high-force wing cam 39 is fixed on the seventh shaft 33. The cam 39 has a surface 40 engaging the cam groove 37 on the stop 36 with low-friction inclined-plane mechanical advantage. The wing carn 39 is adapted to normally hold the stop 36 in the normal position. Angular movement of the cam 39 moves the stop 36 to the alarm position.

A heat-reactive bimetal coil 41 has opposite ends with one end anchored to the plate 11 or 12 at 52 and the other end connected to the wing cam 39 through the seventh shaft 51. The bimetal coil 41 is adapted to hold the wing cam 39 and stop 36 in the normal position at nondangerous temperatures and to angularly move the wing cam 3'9 to move the stop 36 to the alarm position at dangerous temperatures to release the stop leg 34 to free the hammer arm 29 to oscillate with its impact end 33 impinging on the bell flange 32 to create a loud ringing sound of alarm.

FIGS. 2 and 6 show the cam 39 positioning the stop 36 against the stop leg 34 to prevent oscillation of the hammer arm 29. FIGS. 3 and 7 show the cam positioning the stop 36 away from the leg 34 to allow oscillation of the hammer arm 29. In this regard it will be understood that the leg 34 to complete its oscillation in one direction must move to the position seen in FIG. 7 adjacent the shaft 35. Since the leg 34 can move to this position in FIG. 7, this is the alarm position of the stop 36 and cam 39. Conversely, the leg 34 in FIG. 6 cannot move to a point adjacent the shaft 35 because it is blocked by the stop 36. This prevents the leg 34 making it full movement of oscillation in one direction and thus prevents oscillation of the leg 34 and consequently prevents oscillation of the hammer arm 29 and prevents the sounding of the alarm. This later is the normal position of the cam 34 and stop 36.

An auxiliary dial thermometer is carried by the bell housing 30 central portion 31 and comprises a dial 60 on the central portion 31, a hand 61, a stud 62, and a bimetal coil 63 adapted to control the hand 61 relative to the dial 60. This thermometer is independent of the alarm device but provides visual temperature readings.

While only a preferred embodiment of the alarm device has been shown and described, it will be understood that the invention is defined by the scope of the appended claims.

lclaim:

l. A self-contained independently operable, audible-sound fire-alarm device sensitive to dangerously high temperatures to sound the alarm comprising,

paired spaced frame plates,

studs and spacers securing said plates,

a spring-powered motor positioned between said plates having a winding shaft, a coil spring having opposite ends with one end anchored to said shaft, a drive gear free on said shaft; said other end of said spring being connected to said drive gear; a ratchet on said winding shaft preventing rotation of said winding shaft in the unwinding direction;

a second shaft between said plates,

a reduction gear set on said second shaft in engagement with said drive gear;

a third shaft between said plates, a pinion gear on said third shaft in engagement with said reduction gear set, and escapement star wheel connected to said pinion gear;

a fourth shaft between said plates, an escapement lever pivoted thereon; said escapement lever having a clevis end in driven engagement with said star wheel and an opposite end;

a fifth shaft between said plates, a hammer arm having opposite ends with one end pivoted on said fifth shaft and said other end swingable outwardly of said plates; said hammer arm other end being an impact end;

said escapement lever being pivotally connected to said hammer arm to oscillate said hammer arm;

a bell housing having a central portion secured to one said plate and a flange portion surrounding said plates adapted to be hit by said hammer impact end;

said star wheel upon rotation alternately camming said clevis ends of said escapement lever to oscillate said escapement lever to, in turn, oscillate said hammer arm to move said hammer arm impact and against said flange of said bell housing to create a loud ringing sound of alarm;

a stop leg connected to said hammer arm,

a sixth shaft between said plates, a stop axially slidably disposed on said sixth shaft having a normal axial position engaging said stop leg to prevent oscillation of said hammer arm and an alarm axial position out of engagement with said stop leg to permit oscillation of said hammer arm;

said stop having a cam groove,

a seventh shaft between said plates, a low-friction highforce wing cam fixed on said seventh shaft; said cam having a surface engaging said cam groove on said stop with low-angle inclined-plane mechanical advantage,

said wing cam being adapted to normally hold said stop in normal position; said wing cam with angular movement of said cam being adapted to move said stop to the alarm position, and

a heat-reactive bimetal coil having opposite ends with one said end anchored to one said plate and the other end connected to said wing cam through said seventh shaft;

said bimetal coil being adapted to hold said wing cam and stop in the normal position at nondangerous temperatures and to angularly move said wing cam to move said stop to the alarm position at dangerous temperatures to release said stop leg to free said hammer arm to oscillate with its impact end impinging on said bell housing to create a loud ringing sound of alarm.

2. A fire-alarm device sensitive to dangerously high ternl peratures to sound an alarm comprising,

a frame, a motor on said frame,

a drive gear powered by said motor, a reduction gear set on sard frame in engagement wrth sard drive gear;

a pinion gear on said frame in engagement with said reduction gear set, an escapement star wheel connected to said pinion gear;

an escapement lever pivoted on said frame; said escapement lever having a clevis end in driven engagement with said star wheel and an opposite end;

a hammer arm having opposite ends with one end pivoted on said frame and said other end swingable outwardly of said frame; said hammer arm other end being an impact end;

said escapement lever being pivotally connected to said hammer arm to oscillate said hammer arm;

a bell housing having a central portion secured to said frame and a flange portion adapted to be hit by said hammer impact end;

said star wheel upon rotation alternately camming said clevis ends of said escapement lever to oscillate said escapement lever to oscillate said hammer arm to move said hammer arm impact end against said flange of said bell housing to create a loud ringing sound of alarm;

a stop leg connected to said hammer arm,

a stop axially slidably disposed on said frame having a normal axial position engaging said stop leg to prevent oscillation of said hammer arm and an alarm axial position out of engagement with said stop leg to permit oscillation of said hammer arm;

said stop having a cam-engaging means,

a low-friction high-force wing cam pivoted on said frame; said cam having a surface engaging cam-engaging means on said stop with low-angle inclined-plane mechanical advantage,

said wing cam being adapted to normally hold said stop in normal position; said wing cam with angular movement of said cam being adapted to move said stop to the alarm position, and

a heat-reactive bimetal coil having opposite ends with one said end anchored to one said frame and the other end connected to said wing cam;

said bimetal coil being adapted to hold said wing cam and stop in the normal position at nondangerous temperatures and to angularly move said wing cam to move said stop to the alarm position at dangerous temperatures to release said stop leg to free said hammer arm to oscillate with its impact end impinging on said bell housing to create a loud ringing sound of alarm.

lOIOIS 0082 

1. A self-contained independently operable, audible-sound firealarm device sensitive to dangerously high temperatures to sound the alarm comprising, paired spaced frame plates, studs and spacers securing said plates, a spring-powered motor positioned between said plates having a winding shaft, a coil spring having opposite ends with one end anchored to said shaft, a drive gear free on said shaft; said other end of said spring being connected to said drive gear; a ratchet on said winding shaft preventing rotation of said winding shaft in the unwinding direction; a second shaft between said plates, a reduction gear set on said second shaft in engagement with said drive gear; a third shaft between said plates, a pinion gear on said third shaft in engagement with said reduction gear set, and escapement star wheel connected to said pinion gear; a fourth shaft between said plates, an escapement lever pivoted thereon; said escapement lever having a clevis end in driven engagement with said star wheel and an opposite end; a fifth shaft between said plates, a hammer arm having opposite ends with one end pivoted on said fifth shaft and said other end swingable outwardly of said plates; said hammer arm other end being an impact end; said escapement lever being pivotally connected to said hammer arm to oscillate said hammer arm; a bell housing having a central portion secured to one said plate and a flange portion surrounding said plates adapted to be hit by said hammer impact end; said star wheel upon rotation alternately camming said clevis ends of said escapement lever to oscillate said escapement lever to, in turn, oscillate said hammer arm to move said hammer arm impact end against said flange of said bell housing to create a loud ringing sound of alarm; a stop leg connected to said hamMer arm, a sixth shaft between said plates, a stop axially slidably disposed on said sixth shaft having a normal axial position engaging said stop leg to prevent oscillation of said hammer arm and an alarm axial position out of engagement with said stop leg to permit oscillation of said hammer arm; said stop having a cam groove, a seventh shaft between said plates, a low-friction high-force wing cam fixed on said seventh shaft; said cam having a surface engaging said cam groove on said stop with low-angle inclinedplane mechanical advantage, said wing cam being adapted to normally hold said stop in normal position; said wing cam with angular movement of said cam being adapted to move said stop to the alarm position, and a heat-reactive bimetal coil having opposite ends with one said end anchored to one said plate and the other end connected to said wing cam through said seventh shaft; said bimetal coil being adapted to hold said wing cam and stop in the normal position at nondangerous temperatures and to angularly move said wing cam to move said stop to the alarm position at dangerous temperatures to release said stop leg to free said hammer arm to oscillate with its impact end impinging on said bell housing to create a loud ringing sound of alarm.
 2. A fire-alarm device sensitive to dangerously high temperatures to sound an alarm comprising, a frame, a motor on said frame, a drive gear powered by said motor, a reduction gear set on said frame in engagement with said drive gear; a pinion gear on said frame in engagement with said reduction gear set, an escapement star wheel connected to said pinion gear; an escapement lever pivoted on said frame; said escapement lever having a clevis end in driven engagement with said star wheel and an opposite end; a hammer arm having opposite ends with one end pivoted on said frame and said other end swingable outwardly of said frame; said hammer arm other end being an impact end; said escapement lever being pivotally connected to said hammer arm to oscillate said hammer arm; a bell housing having a central portion secured to said frame and a flange portion adapted to be hit by said hammer impact end; said star wheel upon rotation alternately camming said clevis ends of said escapement lever to oscillate said escapement lever to oscillate said hammer arm to move said hammer arm impact end against said flange of said bell housing to create a loud ringing sound of alarm; a stop leg connected to said hammer arm, a stop axially slidably disposed on said frame having a normal axial position engaging said stop leg to prevent oscillation of said hammer arm and an alarm axial position out of engagement with said stop leg to permit oscillation of said hammer arm; said stop having a cam-engaging means, a low-friction high-force wing cam pivoted on said frame; said cam having a surface engaging cam-engaging means on said stop with low-angle inclined-plane mechanical advantage, said wing cam being adapted to normally hold said stop in normal position; said wing cam with angular movement of said cam being adapted to move said stop to the alarm position, and a heat-reactive bimetal coil having opposite ends with one said end anchored to one said frame and the other end connected to said wing cam; said bimetal coil being adapted to hold said wing cam and stop in the normal position at nondangerous temperatures and to angularly move said wing cam to move said stop to the alarm position at dangerous temperatures to release said stop leg to free said hammer arm to oscillate with its impact end impinging on said bell housing to create a loud ringing sound of alarm. 